Since then he's overseen an upturn in fortunes for the national side, leading South Africa in victories over New Zealand, Australia, and a series win against England.

Yet Kolisi, who was raised by his grandmother, still remembers a time before he found salvation through the sport.

"There were nights where I was worried like, am I going to eat all day?

"My grandma would go and visit her friends in the township ... they'll make tea and maybe a slice of bread and butter. She would take that, wrap it in paper, put it in her pocket and bring it home for me. That would be my meal for the day."

'A symbol of hope'

The country's rugby's team has a long history of segregation, with white and "non-racial" teams competing separately to each other until the 1990s.

There was just one black player, Chester Williams, in the side that won the 1995 World Cup, yet that triumph was seen as a turning point for South Africa as Nelson Mandela presented the trophy wearing the Springbok jersey -- a shirt that previously symbolized white Afrikaner nationalism.

It was a moment that inspired legendary Springbok Bryan Habana, one of the two black players to play in the 2007 World Cup final. For Habana, Kolisi's journey is a significant one for South African sport.

"Having Siya with his story of having come from previously disadvantaged backgrounds and communities, to then overcome all those odds and grab the opportunity ... It's something truly, truly special," Habana, the country's top try scorer, tells CNN World Rugby.

"I think under his guidance and through his story, this current crop of Springbok players know that, yes, they're Springboks, but they're now a symbol of hope to this country. It's more than just that jersey they wear. It's the story they're telling."

Breaking barriers

After earning a scholarship to Grey High School in Port Elizabeth, Kolisi fell in love with rugby. While competing for the school team, he would also sneak away to play for his township club African Bombers.

Aged just 15, he found himself playing three games a day, often being pitted against grown men twice his size.

Rising through the junior ranks of South African rugby, Kolisi went on to represent Western Province and his current club Stormers before earning his first Springbok cap in 2013.

An established member of the squad, Kolisi was nevertheless stunned when coach Rassie Erasmus handed him the captaincy last year. When he rang his wife Rachel to tell her the news, she refused to believe him and put the phone down.

"People had obviously high expectations and everything, and I think seeing myself in newspapers every single day, it's something I wasn't used to.

"My game went a little bit down, and it was tough. You can see with the stats and stuff. Even the coach would tell you that my game wasn't up to standard."

Yet as a leader, Kolisi has been an ideal recruit for South Africa. While last year's results weren't perfect, the improvement has been vast.

In particular, victory away to New Zealand -- who the Springboks face in their first game at the World Cup later this year -- galvanized the squad.

"We've broken through some barriers I thought we couldn't do," says Kolisi. "The respect is back in the Springbok jersey.

"I think we're getting it right without trying. We're not trying to be something. It's just coming. It's working for us because we're a young team and we get along so well. And we just want to grow. We want to make sure that the Springboks are the best.

Superman

Kolisi's success as a captain owes to his popularity within the squad and the bond he fosters with each player individually.

"The best way is to get to know people. Get to know who they are," he says.

"That's what makes me a bit different, because I get along with every single guy on the team, and I'm black. Normally there are groups, but I can go to every single group ... you understand each other a bit more, and they understand me a bit more."

Kolisi's rugby commitments take him all around the world, and he laments the amount of time he has to spend away from his wife and four children.

His eldest son, says Kolisi, "thinks I'm Superman and thinks I can't get hurt." Father and son will often FaceTime when he's away on camp, both wearing their South Africa kits.

Kolisi adopted his half-brother and half-sister in 2014 having not seen them for seven years. Visiting the foster home is a moment he recalls fondly: "[my sister] walked up to me, and she started touching my face. My heart just melted."

With family and teammates alike, Kolisi is warm and generous. Perhaps it's an attitude he picked up from his grandmother all those years ago when she would bring him back a piece of bread -- his only meal of the day.

"My grandma taught me one thing," he says, "love. If someone gives you love, that's all you need."